The present invention relates to the general field of rapid prototyping (RP), and methods and systems of dispensing fluid media such as direct-write (DW) technologies.
RP technologies, also known as Solid Freeform Fabrication (SFF), layered manufacturing and other similar technologies enable the manufacture of complex three-dimensional (3D) parts. RP technologies, in particular, generally construct parts by building one layer at a time for use in, for example, the toy, automotive, aircraft and medical industries. Oftentimes prototypes made by RP technologies aid in research and development and provide a low cost alternative to traditional prototyping.
Stereolithography (SL) is one of the most widely used RP technologies known in the art. The resolution of SL machines and the ability of SL to manufacture highly complex 3D objects, make SL ideal for building both functional and non-functional prototypes. In particular, SL techniques provide economical, physical models of objects quickly prior to making more expensive finished parts. The models are readily customizable and changes may be easily implemented.
SL generally involves a multi-stage process. For example, the first stage involves designing and inputting a precise mathematical and geometric description of the desired structure's shape into one of many computer-aided design (CAD) programs and saving the description in the standard transform language (STL) file format. In the second stage, the STL file is imported into SL machine-specific software (RP software). The RP software slices the design into layers and determines the placement of support structures to hold each cross-section in place while building the structure layer by layer. By computing build parameters, the RP software controls the part's fabrication. In the layer preparation stage, the build parameters for the desired part are translated into machine language. Finally, the machine language controls the SL machine to build a desired part and its support structures layer by layer. SL machines typically focus an ultraviolet (UV) laser onto a cross-section of a liquid photopolymer resin. The laser, in turn, selectively cures a resin to form a structure, layer by layer. Ultimately, the part is cleaned, the support structure is removed and the part is post-cured (typically exposed to UV) prior to completion. Complex-shaped parts are thus manufactured by repeating the layering process.
Although RP technologies for complex functional parts and prototypes have greatly improved in recent years, there is still a need to improve RP technologies for building functional electromechanical parts. There is a further need for achieving significant reductions in size, mass and manufacturing cycle times of low voltage electrical systems. Most RP systems allow building cycle sequences to be interrupted, thus opening the possibility of encapsulating electromechanical components within the model structure. For example, some have demonstrated the feasibility of encapsulating sensors and actuators in metal and polymer structures using Shape Deposition Manufacturing (SDM). Others have demonstrated systems for automatic dispensing of conductive, thermally curable media, such as direct-write (DW) inks, for maskless patterning of electronics. Limitations in speed and feature size, however, have prevented the integration of RP and DW technologies and, consequently, its acceptance in, for example, the microelectronics industry. Recently, however, there have been several breakthroughs in DW ink dispensing for military applications which dispense advanced metallic inks through a hollow tip, precisely controlling the ink's flow and stopping points. These breakthroughs may lead to writing capabilities as small as 50 micrometers on curved substrates of various materials. Although there have been improvements in writing capabilities, many SL resins have been found to be incompatible with, for example, the high temperatures required to anneal DW inks.
What is desired is a system and method for automated deposition of fluid media during any RP processing, automated curing of the media (if necessary), encapsulation of the media and continued building without contamination or intermediate washing and/or curing. What is also desired are improvements in part building technology and, in particular, improvements in the integration of fluid media, such as DW inks, with RP technologies. Specifically, there is a need for low cost, efficient and easy to use RP processes that accommodate 3D DW ink dispensing technology to fabricate, for example, complex 3D, high density circuits that are rapidly manufactured, integrated and fully functional electromechanical systems. Such electromechanical systems should be compact, less expensive and more reliable than their conventional predecessors. Additionally, by removing heavy cables, redundancy can easily be designed into a structure where previously it could not be, thus allowing significant size and weight savings for sensitive applications such as those for aerospace and space applications.
What is further desired is a system and method for Rapid Prototyping High Density Circuit (RPHDC) manufacturing of solderless connectors and pilot devices with terminal geometries that are compatible with DW mechanisms and reduce contact resistance where the electrical system is encapsulated within structural members and manual electrical connections are eliminated in favor of automated DW traces.